The present invention relates to a light connecting device with an optical processing device.
In recent years, development of a computerized society has resulted in a demand for systems and devices such as an input/output device, a transmission device, a packet system, and a signal processing system having a greater capacity for processing information at higher speeds. To fulfill this demand, information is being processed using optics instead of electronics. At present, optical communications by optical fiber is widely used for transmitting information. However, the use of light may be limited to transportation of the information. Switching stations and packet systems are still controlled by conventional electronics circuits. Therefore, high speed optical processing is not realized due to a lower processing speed of the electronics circuits.
Although use of light for exchanging information provides high speed communication, such a system has not yet been proposed because optical devices are not only required to generate and receive light but also process threshold value and memory. For the optical device to respond to this demand, a photoelectric input/output element with a bi-stable laser and light thyristor has been developed. For an example of a bi-stable laser, see "Full Optical Type Flip-Flop Using Bi-Stable Laser", Review of Articles, Volume C-1, page 48, published at the national meeting of the Institute of Electronics, Information and Communication Engineers (IEICE) in Autumn 1988. A light exchange control may have a self-routing system where addresses and signals are loaded upon transmitting information. However, this system is not proposed in the bi-stable laser. This self-routing system requires accurate control of the wavelength of light.
An example of the light connecting element is described in detail in "Double Heterostructure Optoelectronic Switch As A Dynamic Memory With Low-Power Consumption", Applied Physics Letters, Volume 52, pages 679-681, 1988.
For an example of the light connecting element using the photoelectric input/output elements, see "Optical Self-Routing Switch With Wavelength Filtering Function Using VSTEPS", Institute of Applied Physics Engineers, Volume 3, page 754, 1990. The element construction, as shown in FIG. 1, performs a self-routing operation to determine the address of information by inputting light and electricity. Voltage pulses 51 and 52 in FIG. 1 are input into light input/output elements 61 and 62 in time series. In synchronization with the voltage pulses, address signal light 53 having address information is incident on the elements 61 and 62. The photoelectric input/output elements simultaneously receiving voltage pulses and an address signal light are selectively turned ON to operate. The elements turned ON receive a current equal to the laser oscillation threshold value or less and operate as a light amplifier. Thus, the received information signals 54 are amplified and then output.
However, since the self-routing device with the photoelectric input/output elements requires a synchronizing address signal light with an applied voltage, the self-routing device has problems, such as lower speed and a complicated structure resulting from circuits used for synchronizing the applied voltage.